<!DOCTYPE html>
<html lang="en">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <title>鼠标框选效果</title>
    <style>
        *{
            padding:0;
            margin:0;
        }
        #bottom{
            position:absolute;
            bottom:0;
            width:100%;
            height:40px;
            border:1px solid #000;
            background:#000;
            color:#fff;
        }
        .tempDiv{
            border:1px dashed blue;
            background:#5a72f8;
            position:absolute;
            width:0;
            height:0;
            filter:alpha(opacity:10);
            opacity:0.1
        }
    </style>
    <script type = "text/javascript">
        window.onload = function(){
            var stateBar = document.getElementById("bottom");
            document.onmousedown = function(e){
                var posx = e.clientX;
                var posy = e.clientY;
                var div = document.createElement("div");
                div.className = "tempDiv";
                div.style.left = e.clientX+"px";
                div.style.top = e.clientY+"px";
                document.body.appendChild(div);
                document.onmousemove = function(ev){
                    div.style.left = Math.min(ev.clientX, posx) + "px";
                    div.style.top = Math.min(ev.clientY, posy) + "px";
                    div.style.width = Math.abs(posx - ev.clientX)+"px";
                    div.style.height = Math.abs(posy - ev.clientY)+"px";
                    stateBar.innerHTML = "MouseX: " + ev.clientX + "<br/>MouseY: " + ev.clientY;
                    document.onmouseup = function(){
                        div.parentNode.removeChild(div);
                        document.onmousemove = null;
                        document.onmouseup = null;
                    }
                }
            }
        }
    </script>
</head>
<body>
<div id = "bottom"></div>
</body>
</html>

